Merge branch 'gup_flag-cleanups'

Merge the gup_flags cleanups from Lorenzo Stoakes:
 "This patch series adjusts functions in the get_user_pages* family such
  that desired FOLL_* flags are passed as an argument rather than
  implied by flags.

  The purpose of this change is to make the use of FOLL_FORCE explicit
  so it is easier to grep for and clearer to callers that this flag is
  being used.  The use of FOLL_FORCE is an issue as it overrides missing
  VM_READ/VM_WRITE flags for the VMA whose pages we are reading
  from/writing to, which can result in surprising behaviour.

  The patch series came out of the discussion around commit 38e088546522
  ("mm: check VMA flags to avoid invalid PROT_NONE NUMA balancing"),
  which addressed a BUG_ON() being triggered when a page was faulted in
  with PROT_NONE set but having been overridden by FOLL_FORCE.
  do_numa_page() was run on the assumption the page _must_ be one marked
  for NUMA node migration as an actual PROT_NONE page would have been
  dealt with prior to this code path, however FOLL_FORCE introduced a
  situation where this assumption did not hold.

  See

      https://marc.info/?l=linux-mm&m=147585445805166

  for the patch proposal"

Additionally, there's a fix for an ancient bug related to FOLL_FORCE and
FOLL_WRITE by me.

[ This branch was rebased recently to add a few more acked-by's and
  reviewed-by's ]

* gup_flag-cleanups:
  mm: replace access_process_vm() write parameter with gup_flags
  mm: replace access_remote_vm() write parameter with gup_flags
  mm: replace __access_remote_vm() write parameter with gup_flags
  mm: replace get_user_pages_remote() write/force parameters with gup_flags
  mm: replace get_user_pages() write/force parameters with gup_flags
  mm: replace get_vaddr_frames() write/force parameters with gup_flags
  mm: replace get_user_pages_locked() write/force parameters with gup_flags
  mm: replace get_user_pages_unlocked() write/force parameters with gup_flags
  mm: remove write/force parameters from __get_user_pages_unlocked()
  mm: remove write/force parameters from __get_user_pages_locked()
  mm: remove gup_flags FOLL_WRITE games from __get_user_pages()

6 files changed, 21 insertions, 9 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index 887483b8b818..dcaf691f56b5 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -555,10 +555,13 @@ struct amdgpu_ttm_tt {
 int amdgpu_ttm_tt_get_user_pages(struct ttm_tt *ttm, struct page **pages)
 {
 	struct amdgpu_ttm_tt *gtt = (void *)ttm;
-	int write = !(gtt->userflags & AMDGPU_GEM_USERPTR_READONLY);
+	unsigned int flags = 0;
 	unsigned pinned = 0;
 	int r;
 
+	if (!(gtt->userflags & AMDGPU_GEM_USERPTR_READONLY))
+		flags |= FOLL_WRITE;
+
 	if (gtt->userflags & AMDGPU_GEM_USERPTR_ANONONLY) {
 		/* check that we only use anonymous memory
 		   to prevent problems with writeback */
@@ -581,7 +584,7 @@ int amdgpu_ttm_tt_get_user_pages(struct ttm_tt *ttm, struct page **pages)
 		list_add(&guptask.list, &gtt->guptasks);
 		spin_unlock(&gtt->guptasklock);
 
-		r = get_user_pages(userptr, num_pages, write, 0, p, NULL);
+		r = get_user_pages(userptr, num_pages, flags, p, NULL);
 
 		spin_lock(&gtt->guptasklock);
 		list_del(&guptask.list);
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gem.c b/drivers/gpu/drm/etnaviv/etnaviv_gem.c
index 5ce3603e6eac..0370b842d9cc 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_gem.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gem.c
@@ -748,19 +748,22 @@ static struct page **etnaviv_gem_userptr_do_get_pages(
 	int ret = 0, pinned, npages = etnaviv_obj->base.size >> PAGE_SHIFT;
 	struct page **pvec;
 	uintptr_t ptr;
+	unsigned int flags = 0;
 
 	pvec = drm_malloc_ab(npages, sizeof(struct page *));
 	if (!pvec)
 		return ERR_PTR(-ENOMEM);
 
+	if (!etnaviv_obj->userptr.ro)
+		flags |= FOLL_WRITE;
+
 	pinned = 0;
 	ptr = etnaviv_obj->userptr.ptr;
 
 	down_read(&mm->mmap_sem);
 	while (pinned < npages) {
 		ret = get_user_pages_remote(task, mm, ptr, npages - pinned,
-					    !etnaviv_obj->userptr.ro, 0,
-					    pvec + pinned, NULL);
+					    flags, pvec + pinned, NULL);
 		if (ret < 0)
 			break;
 
diff --git a/drivers/gpu/drm/exynos/exynos_drm_g2d.c b/drivers/gpu/drm/exynos/exynos_drm_g2d.c
index aa92decf4233..fbd13fabdf2d 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_g2d.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_g2d.c
@@ -488,7 +488,8 @@ static dma_addr_t *g2d_userptr_get_dma_addr(struct drm_device *drm_dev,
 		goto err_free;
 	}
 
-	ret = get_vaddr_frames(start, npages, true, true, g2d_userptr->vec);
+	ret = get_vaddr_frames(start, npages, FOLL_FORCE | FOLL_WRITE,
+		g2d_userptr->vec);
 	if (ret != npages) {
 		DRM_ERROR("failed to get user pages from userptr.\n");
 		if (ret < 0)
diff --git a/drivers/gpu/drm/i915/i915_gem_userptr.c b/drivers/gpu/drm/i915/i915_gem_userptr.c
index e537930c64b5..c6f780f5abc9 100644
--- a/drivers/gpu/drm/i915/i915_gem_userptr.c
+++ b/drivers/gpu/drm/i915/i915_gem_userptr.c
@@ -508,6 +508,10 @@ __i915_gem_userptr_get_pages_worker(struct work_struct *_work)
 	pvec = drm_malloc_gfp(npages, sizeof(struct page *), GFP_TEMPORARY);
 	if (pvec != NULL) {
 		struct mm_struct *mm = obj->userptr.mm->mm;
+		unsigned int flags = 0;
+
+		if (!obj->userptr.read_only)
+			flags |= FOLL_WRITE;
 
 		ret = -EFAULT;
 		if (atomic_inc_not_zero(&mm->mm_users)) {
@@ -517,7 +521,7 @@ __i915_gem_userptr_get_pages_worker(struct work_struct *_work)
 					(work->task, mm,
 					 obj->userptr.ptr + pinned * PAGE_SIZE,
 					 npages - pinned,
-					 !obj->userptr.read_only, 0,
+					 flags,
 					 pvec + pinned, NULL);
 				if (ret < 0)
 					break;
diff --git a/drivers/gpu/drm/radeon/radeon_ttm.c b/drivers/gpu/drm/radeon/radeon_ttm.c
index 455268214b89..3de5e6e21662 100644
--- a/drivers/gpu/drm/radeon/radeon_ttm.c
+++ b/drivers/gpu/drm/radeon/radeon_ttm.c
@@ -566,7 +566,8 @@ static int radeon_ttm_tt_pin_userptr(struct ttm_tt *ttm)
 		uint64_t userptr = gtt->userptr + pinned * PAGE_SIZE;
 		struct page **pages = ttm->pages + pinned;
 
-		r = get_user_pages(userptr, num_pages, write, 0, pages, NULL);
+		r = get_user_pages(userptr, num_pages, write ? FOLL_WRITE : 0,
+				   pages, NULL);
 		if (r < 0)
 			goto release_pages;
 
diff --git a/drivers/gpu/drm/via/via_dmablit.c b/drivers/gpu/drm/via/via_dmablit.c
index 7e2a12c4fed2..1a3ad769f8c8 100644
--- a/drivers/gpu/drm/via/via_dmablit.c
+++ b/drivers/gpu/drm/via/via_dmablit.c
@@ -241,8 +241,8 @@ via_lock_all_dma_pages(drm_via_sg_info_t *vsg,  drm_via_dmablit_t *xfer)
 	down_read(&current->mm->mmap_sem);
 	ret = get_user_pages((unsigned long)xfer->mem_addr,
 			     vsg->num_pages,
-			     (vsg->direction == DMA_FROM_DEVICE),
-			     0, vsg->pages, NULL);
+			     (vsg->direction == DMA_FROM_DEVICE) ? FOLL_WRITE : 0,
+			     vsg->pages, NULL);
 
 	up_read(&current->mm->mmap_sem);
 	if (ret != vsg->num_pages) {